1. Field of the Invention
This invention relates to a signal processing method in autoradiography, and more particularly to a signal processing method in autoradiography employing a radiosensitive material.
2. Description of the Prior Art
Autoradiography has been known as a method for obtaining locational information or radioactively labeled substances distributed in at least one dimensional direction to form distributed rows on a support medium.
For instance, autoradiography comprises steps of; labeling organism-originating biopolymers such as proteins or nucleic acids with a radioactive element; resolving the radioactively labeled biopolymers, derivatives thereof, or cleavage products thereof on a gel support (support medium) through a resolving process such as gel electrophoresis; placing the gel support and a high-sensitivity type X-ray film together in layers for a certain period of time to expose said film, developing said film, obtaining the locational information of the radioactively labeled substances from the developed film, and then performing the identification of the polymeric substances, determination of molecular weight thereof and isolation thereof based on the obtained locational information.
Autoradiography has a prominent advantage in that visual observation of the locational information in a cell scale or a molecular scale on radioactively labeled substances can be made by utilizing the radiography as mentioned above. However, in other words, it is essential in the autoradiography utilizing the radiography to visualize the autoradiograph having the locational information on a radiographic film in order to obtain the locational information on the radioactively labeled substances.
In fact, the investigators have determined the distribution of the radioactively labeled substances in a sampled by observing a visualized autoradiograph with eyes to obtain the locational information on the specific substances labeled with a radioactive element.
A certain locational information as obtained above has been further subjected to various analyses to isolate or identify radioactively labeled substances, or to determine the molecular weight or characteristics of specific substances. For instance, the above-mentioned autoradiography is used effective to determine the base sequence of nucleic acids such as DNA, and the method is considered to be of a value for determination of structure of polymeric substances originating from organisms. The determination of structure of such substances likewise requires the visual determination.
Accordingly, the autoradiography is a useful method for analysis of the structure and function of tissue of organisms and/or of organism-originating substances, but it has unfavorable feature that the autoradiography requires visual analysis, thereby needing a great amount of time and labor.
Further, the locational information obtained by the analysis of the autoradiograph varies depending on the investigators in charge because of inherent unreliability of visual observation, and the accuracy of the information is limited to a certain extent. Particularly, in such a case that only a small quantity of a sample has been employed, that the intensity of radiation energy emitted by radioactively labeled substances has been low, or that the exposure has been done under unfavorable conditions, an autoradiographic image visualized on a radiographic material has reduced quality (in regard to sharpness, contrast, etc.) so that satisfactory information can not be obtained and the accuracy is low. These are drawbacks of the autoradiography.
In order to improve the accuracy of the locational information, for instance, a visualized autoradiograph can be scanned by means of a device such as a scanning densitometer. However, such scanning process requires increased time and complicated procedures.